Engine replaced at 80K/ Check Engine Light on/ put on computer/oxygen sensor/ low Baro feedback.

monalisavito2monalisavito2 Member Posts: 2
edited July 2014 in Cadillac

Car had engine replaced with another used motor (w/warranty). Intial Engine have DTC P0304. After all the plugs replaced, coil packs checked, and injectors cleaned we did compression test that showed no compression on CYL 4. Decided we were most likely dealing with worn rings or cracked head gasket we decided to buy another motor.
No sensor codes ever showed. New motor goes in, with original sensors and such. Engine light still on. Cleared the codes, light went out. We were very low on gas at this point. Bought a can of seafoam and dumped it in the tank, then filled up. I was worried that putting seafoam in FIRST,then filling up... would make that first shot of fuel not ignite. Guess what? The car would not start at the pump! Tried three times. It started and then we went to check code on computer for the engine light reappearing...reads only two things Oxygen sensor and Baro low something. Sorry, I don't have the print out.ANY CHANCE that SEAFOAM just didn't mix well since it was put in empty tank then the gas??? Since all sensors had to be unplugged for the engine replacement, I am wondering if something hasn't just rattled loose or was not connected well by mechanic being in a rush..Mechanic said he will check the sensors tomorrow. No worries as car ran great yesterday (1st day driven after install).

TODAY drove short distance and got reduced engine power low oil pressure...then car slowwws. Pulled over. car idling yet when press on gas ...nothing, cant't be driven. Will need a tow. I am assuming that this mostly will be a loose clip(sensor) bad ground. Other possible things I've read indicate catalytic converter clogged / Idle control body and a suggestion to check wire harness.One guy claims rust build up under front abs sensors.Reading forums can be confusing. I think I am finding good leads and this is why I am becoming MonaLisaVito from My Cousin Vinny, haha! Thanks in advance for the help.


  • monalisavito2monalisavito2 Member Posts: 2

    Just to be clear the car drove well for the one we drove it day, Saturday, after engine was replaced on Friday. Sunday the SRX slowwed down right after we took a turn from a high incline run. Display messages were "Reduced engine power" as we pulled to the roadside,followed by "zero oil compression" as it idled. Thought about positioning car better after coming to a complete stop roadside, but upon trying to accererate....nothing would happen. Left the vehicle there last night. This morning the vehicle would accelerate to allow us to better position it for a tow. Although it accelerated we did not want to chance driving it with zero oil compression so...there it sits waiting on a tow. Any suggestions?! I am new on this site. I am hoping it's a sensor thing has become detached as I don't want the replaced motor to be bad, and have to start this process alllll over again. UGHHHH!

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